For your first BP I personally would buy from a reputable breeder. You know it is healthy, feeding if a hatchling, and no mites. It is hard when you are new to know what to look for in a sick BP and what to do when there are problems.
As far as going away.....It is good once you get a new BP to leave it alone for a couple of weeks without touching it. This is really the hardest thing to do so going away might give it time to adjust quietly without disruptions. I would personally have someone come in and check to make sure there are no fluctuations in the temps and to make sure the water bowl is full maybe a mid vacation check.
Also I am sure that you have seen this but this is a great tool for a new owner. Congrats and good luck...it is just the beginning for you as they are totally addictive.
http://www.ball-pythons.net/modules/...warticle&id=59